How to get next and previous page in a Train Flow .

Question

Hi,
For creating record I am using multi-step flow (train).
I have three page and I want to navigate the page via multi-step flow (train).
I followed the steps given in the Toolbox Tutorial of create purchase order and
Locator Element: Page/Record Navigation in developer's guide.
page1=/uttara/oracle/apps/uttaraimc/createcitizen/webui/PropertyCreatePG
page2=/uttara/oracle/apps/uttaraimc/createcitizen/webui/HouseDetailsCreatePG"
page3=/uttara/oracle/apps/uttaraimc/createcitizen/webui/EducationCreatePG"
The page1 is navigated via 'Create' button in CitizenSearchPG
Now on this Page1, when I clicks on the 'Next' button (to navigate to the next page in the same multi-step flow) I am getting following exception and its not navigating to page2.
Error: Cannot Display Page
You cannot complete this task because one of the following events caused a loss of page data:
* You accessed this page using the browser's navigation buttons (the browser Back button, for example).
* Your login session has expired.
* A system failure has occurred.
To proceed, please select the Home link at the top of the application page to return to the main menu. Then, access this page again using the application's navigation controls (menu, links, and so on) instead of using the browser's navigation controls like Back and Forward.
Here is the code for CreateFooterCO,
public void processRequest(OAPageContext pageContext, OAWebBean webBean)
super.processRequest(pageContext, webBean);
OANavigationBarBean navBean =
(OANavigationBarBean)webBean.findChildRecursive("NavBar");
if (navBean == null)
MessageToken[] tokens = { new MessageToken("OBJECT_NAME", "NavBar") };
throw new OAException("AK", "FWK_TBX_OBJECT_NOT_FOUND", tokens);
// Determine which page we're on so we can set the selected value. Each
// time we navigate to and within the flow, the URL includes a parameter
// telling us what page we're on.
int step = Integer.parseInt(pageContext.getParameter("ccStep"));
navBean.setValue(step);
// Figure out whether the "Submit" button should be rendered or not;
// this should appear only on the final page (Step 3).
OASubmitButtonBean submitButton =
(OASubmitButtonBean)webBean.findIndexedChildRecursive("Submit");
if (submitButton == null)
MessageToken[] tokens = { new MessageToken("OBJECT_NAME", "Submit") };
throw new OAException("AK", "FWK_TBX_OBJECT_NOT_FOUND", tokens);
if (step != 3)
submitButton.setRendered(false);
public void processFormRequest(OAPageContext pageContext, OAWebBean webBean)
super.processFormRequest(pageContext, webBean);
OAApplicationModule am = pageContext.getApplicationModule(webBean);
int currentStep = Integer.parseInt(pageContext.getParameter("ccStep"));
// This button should only be displayed on the final page...
if (pageContext.getParameter("Submit") != null)
// Simply telling the transaction to commit will cause all the Entity Object validation
     // to fire.
// Note that you must commit before asking WF for the next page, because
// asking for the next page at this point will transition the WF to a
// completed state, which means you won't be able to navigate back
// if there are errors during the commit processing.
am.invokeMethod("apply");
TransactionUnitHelper.endTransactionUnit(pageContext, "citizenCreateTxn");
// Don't forget to call this even on the last page so the activity associated with
// this page completes and the Workflow transitions appropriately.
String nextPage = OANavigation.getNextPage(pageContext);
// For the final page, Workflow should be returning null -- and the user
// can select the "Submit" button only on the last page. Something's
// wrong.
if (nextPage != null)
throw new OAException("AK", "FWK_TBX_T_WF_UNEXPECTED_TRANS");
else // we've just completed the flow
// Assuming the "commit" succeeds, we'll display a Confirmation dialog that takes
     // the user back to the main "Purchase Orders".
/* String poNumber = (String)pageContext.getTransactionValue("PO_NUMBER");
MessageToken[] tokens = { new MessageToken("PO_NUMBER", poNumber),
new MessageToken("PO_APPROVER", pageContext.getUserName()) };
OAException confirmMessage = new OAException("AK", "FWK_TBX_T_PO_CREATE_CONFIRM", tokens);
OADialogPage dialogPage = new OADialogPage(OAException.CONFIRMATION,
confirmMessage,
null,
pageContext.getApplicationJSP() + "?OAFunc=FWK_TOOLBOX_PO_SUMMARY_CR&retainAM=Y",
null);
pageContext.redirectToDialogPage(dialogPage);
else if ("goto".equals(pageContext.getParameter(EVENT_PARAM)) &&
"NavBar".equals(pageContext.getParameter(SOURCE_PARAM)))
// Note that the OANavigationBean publishes a "goto" event paremeter when
// either the Back or Next button is pressed. You need to determine which way to
// go based on the related "value" parameter.
// Also note the check of "source" above to ensure we're dealing with the
// page-level navigation here and not table-level navigation which is
// implemented with the same Bean configured differently.
int target = Integer.parseInt(pageContext.getParameter("value"));
String workflowResult;
if (target < currentStep)
workflowResult = "PREVIOUS";
else
workflowResult = "NEXT";
String nextPage = OANavigation.getNextPage(pageContext, workflowResult);
if (nextPage != null)
HashMap params = new HashMap(1);
params.put("ccStep", IntegerUtils.getInteger(target));
pageContext.setForwardURL(pageContext.getApplicationJSP() + "?" + nextPage, // target page
null,
KEEP_MENU_CONTEXT,
"", // No need to specify since we're keeping menu context
params, // Page parameters
true, // Be sure to retain the AM!
ADD_BREAD_CRUMB_NO, // Do not display breadcrumbs
OAException.ERROR); // Do not forward w/ errors
else
throw new OAException("AK", "FWK_TBX_T_WF_NO_NEXT_PAGE");
else if (pageContext.getParameter("Cancel") != null)
am.invokeMethod("rollbackCitizenInfo");
// Remove the "in transaction" indicator
TransactionUnitHelper.endTransactionUnit(pageContext, "citizenCreateTxn");
pageContext.forwardImmediately("OA.jsp?page=/uttara/oracle/apps/uttaraimc/createcitizen/webui/CreateCitizenSearchPG",
null,
OAWebBeanConstants.KEEP_MENU_CONTEXT,
null,
null,
true, // retain AM
OAWebBeanConstants.ADD_BREAD_CRUMB_NO);
How to resolve this issue?
please suggest.
Thanks & Regards,
Sagarika

Answer 1

Sagarika,
Please go thru the dev guide which explains the train flow in the multistep update exercise. Compare the steps with ur implementation.
- Senthil